Semiconductor device

Abstract

The present disclosure provides a semiconductor device including a semiconductor layer and a trench gate structure. The semiconductor layer includes: a source region extending from a first surface toward a second surface; a drift region and a body region, wherein at least a part of the drift region is located between the body region and the second surface of the semiconductor layer, the body region has a first part located between the source region and the drift region; a channel drain region located between the first part of the body region and the drift region, so that the source region, the first part of the body region and the channel drain region are sequentially adjoining in a direction of the first surface toward the second surface and adjoin a first sidewall of the trench gate structure. The semiconductor device of the present disclosure has better controllability of channel length variation.

What is claimed is: 
     
         1 . A semiconductor device, comprising a semiconductor layer and a trench gate structure, wherein the semiconductor layer has a first surface and a second surface opposite to each other, the trench gate structure is at least partially located in a trench on the first surface of the semiconductor layer,
 the semiconductor layer comprises:   a source region, extending from the first surface toward the second surface;   a drift region and a body region, wherein at least a part of the drift region is located between the body region and the second surface of the semiconductor layer, and the body region has a first part located between the source region and the drift region; and   a channel drain region, located between the first part of the body region and the drift region, so that the source region, the first part of the body region and the channel drain region are sequentially adjoining in a direction of the first surface toward the second surface and adjoin a first sidewall of the trench gate structure,   wherein the source region, the channel drain region, and the drift region are of a first conductivity type, the body region is of a second conductivity type, and the first conductivity type is opposite to the second conductivity type.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein a doping concentration of the channel drain region is greater than a doping concentration of the drift region. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the first part, a second part and a third part of the body region are sequentially adjoining along a width direction of the trench gate structure,
 the second part of the body region adjoins a second sidewall of the trench gate structure and the drift region, respectively,   the third part of the body region extends from a bottom surface of the trench gate structure toward the second surface and adjoins the drift region,   the channel drain region is separated from the third part of the body region by the drift region,   the first sidewall is opposite to the second sidewall.   
     
     
         4 . The semiconductor device according to  claim 3 , wherein the second part of the body region comprises a first sub-region and a second sub-region that are connected,
 the first sub-region adjoins the first part of the body region, the second sub-region adjoins the third part of the body region,   wherein a distance from an edge of the channel drain region facing toward the second surface to the first surface is a first distance,   a distance from an edge of the first sub-region facing toward the second surface to the first surface is a second distance,   a distance from an edge of the second sub-region facing toward the second surface to the first surface is a third distance,   the third distance is greater than the first distance, the first distance is greater than the second distance, so that the channel drain region is separated from the second sub-region by the drift region along the width direction of the trench gate structure.   
     
     
         5 . The semiconductor device according to  claim 1 , wherein edges of the second part and the third part of the body region facing toward the second surface are connected. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein a distance from an edge of the channel drain region facing toward the second surface to the first surface is a first distance,
 a distance from a bottom surface of the trench gate structure to the first surface is a fourth distance,   the first distance is not greater than the fourth distance.   
     
     
         7 . The semiconductor device according to  claim 1 , wherein a distance from an edge of the channel drain region facing toward the second surface to the first surface is a first distance,
 a distance from a bottom surface of the trench gate structure to the first surface is a fourth distance,   the first distance is greater than the fourth distance, and the channel drain region adjoins a part of the bottom surface of the trench gate structure.   
     
     
         8 . The semiconductor device according to  claim 3 , wherein the semiconductor layer further comprises a body contact region extending from the first surface toward the second surface and adjoins the body region,
 wherein the body contact region is of the second conductivity type.   
     
     
         9 . The semiconductor device according to  claim 8 , wherein along an extension direction of the trench gate structure, a part of the body contact region adjoins the second sidewall, another part of the body contact region has a space from the second sidewall, and the part of the body contact region adjoining the second sidewall and the part of the body contact having the space from the second sidewall are arranged alternatively along the extension direction of the trench gate structure,
 or the body contact region is separated from the second surface by the body region.   
     
     
         10 . The semiconductor device according to  claim 8 , wherein the body contact region adjoins the source region, or the body contact region is separated from the source region by the body region. 
     
     
         11 . The semiconductor device according to  claim 1 , wherein the trench gate structure comprises a gate dielectric layer and a gate conductor,
 the gate dielectric layer covers an inner surface of the trench and covers part of first surface adjacent to the trench, the trench extending from the first surface toward the second surface,   a part of the gate conductor is in the trench, another part extends outside the trench and covers the gate dielectric layer,   wherein the gate dielectric layer is located between the gate conductor and the semiconductor layer, so as to separate the gate conductor and the semiconductor layer.   
     
     
         12 . The semiconductor device according to  claim 1 , wherein the semiconductor layer comprises a SiC semiconductor layer. 
     
     
         13 . The semiconductor device according to  claim 1 , wherein the semiconductor device is a metal-oxide semiconductor field effect transistor or an insulated gate bipolar transistor. 
     
     
         14 . The semiconductor device according to  claim 3 , wherein between two trench gate structures, the source region extends from the first sidewall of one trench gate structure towards the second sidewall of the other trench gate structure, and adjoins the second part of the body region.